This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Total knee arthroplasty (TKA) is one of the most common knee surgeries performed in the United States. Patients with TKA exhibit qualitative and quantitative deficits in functional tasks. Shortened stride length and limited knee excursion during weight acceptance is a common finding after TKA. The cause of persistent disability and aberrant movement patterns in individuals who have undergone TKA is unclear, but quadriceps weakness is a likely contributor. Quadriceps weakness is a common and persistent impairment after TKA and has been correlated with poor functional performance in older adults. Weakness is often pronounced even years after knee replacement surgery with deficits ranging from 30% to 40% when compared to age-matched comparison groups. The overall goal of this work is to determine if rehabilitation that normalizes quadriceps strength between limbs after TKA will result in symmetrical loading of the hips and knees and ultimately decrease the progression of contralateral hip and knee OA after primary TKA. Dr. Snyder-Mackler is a full professor and will not have a mentor.